DUBAI, United Arab Emirates (AP) — Kuwait’s 90-year-old ruling emir has cancelled a visit Thursday with President Donald Trump at the White House after being admitted to a U.S. hospital following an earlier health scare last month.

Sheikh Sabah Al Ahmad Al Sabah will undergo unspecified tests during his hospitalization, the state-run KUNA news agency reported late Sunday. It did not elaborate.

It quoted Sheikh Ali Jarrah Al Sabah, the minister of the emir’s diwan council, as saying Sheikh Sabah would reschedule his visit with Trump.

“Sheikh Ali prayed to Allah the Almighty to bestow His Highness the Emir with good health,” KUNA said.

A White House statement said Trump was aware of the emir being hospitalized.

“The president wishes his friend, the Emir, a speedy recovery and looks forward to welcoming him back to Washington as soon as he is feeling better,” the statement said. “The Emir is a well-respected leader and has been a tremendous partner of the United States in tackling challenges in the region.”

That came after visiting Iranian Foreign Minister Mohammad Javad Zarif wrote on Twitter that he was “praying for emir’s speedy recovery,” without elaborating.

Sheikh Sabah has ruled Kuwait since January 2006. A longtime diplomat, he pushed for diplomacy to solve regional issues, such as the ongoing boycott of Qatar by four Arab nations, and hosted major donor conferences for war-torn nations like Iraq and Syria.